Process for improving shelf-life of fresh cut vegetables and food products produced thereby

ABSTRACT

The present disclosure relates to, inter alia, processes for improving shelf-life and flavoring of fresh-cut/fresh vegetables, as well as food products produced by these processes. In accordance with the present disclosure, the processes generally include various new combinations of steps such as blanching, air drying, supercritical fluid processing with and without a processing aid, pressurization, de-pressurization, and packaging. The present disclosure further relates to methods of preparing edible food products that incorporate the processed fresh-cut vegetables, as well as the food products produced by these methods.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority benefit of U.S. Provisional PatentApplication Ser. No. 62/504,889, filed May 11, 2017, the disclosure ofwhich is hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to, inter alia, processes for improvingshelf-life of fresh-cut/fresh vegetables.

BACKGROUND OF THE INVENTION

Fresh vegetables have a short harvest period and have the tendency tospoil quickly if not stored under refrigerated conditions. Somepractical methods for shelf-life extension of fresh vegetables havefound significant commercial application. These methods include modifiedatmosphere packaging (MAP)/controlled atmosphere packaging (CAP), airdrying, freeze drying, vacuum drying, individually quick freezing (IQF),and canning. With MAP/CAP, shelf-life is increased for a few days withrefrigeration from packaging to consumption because microbial growth isdependent on the storage conditions (Oliveira, et al., 2015). Therefrigeration increases the cost of shipping and storing MAP/CAPproducts.

Additionally, when fresh vegetables are peeled and cut, their shelflives are reduced immensely due to the high probability of enhancedenzymatic activity and microbial growth. Methods used for shelf lifeextension of fresh cut vegetables also include air-drying,freeze-drying, vacuum drying, IQF, and canning. Dehydration using air isa commercially used practice but the collateral damage to the taste,nutritional quality, and structural deformation due to shrinkage of theproduct make the process unattractive. Although freeze-drying and vacuumdrying provide better quality products, they suffer from the limitationsin commercial application of being very expensive (Nijhuis, et al.,1998).

U.S. Pat. No. 4,988,523 describes a sulphite-free, anti-browning coatingfor fresh-peeled potatoes. The patent describes a dipping or sprayingprocess employing a mixture of the commercial preservative SPORIX™ andcitric acid. It can protect the color of fresh-peeled potatoes (whole orquartered) for up to 12 days without the use of sulphites and withoutimparting a sulphite-taste to the potato. However, the process requiresthat the potatoes be stored under refrigerated conditions (1-4° C.).

Some other techniques which are commercially practiced include canningand IQF. When compared to fresh produce, frozen vegetables that arelater cooked have relatively poor texture. Furthermore, the cost ofenergy is high for IQF. Similarly, the thermal treatment during canningdeteriorates the textural and nutritional qualities of the product.

U.S. Pat. No. 4,336,273 discloses a process for preserving vegetables byexposing them to a spray, vapor, or pool of organic compounds, such asaldehydes, amides, esters, hydrocarbons, halogenated hydrocarbons,ketones, etc., for 10-20 minutes between 0° to 75° C. Preservation withthis technique requires washing or rinsing the organic compound from thevegetable prior to heat processing. The organic compound must becarefully and completely washed away. The flavors of the vegetables areadversely affected by overexposure to the organic compounds.

U.S. Pat. No. 5,486,369 describes a combination of blanching and dryingto achieve a lower water activity to avoid growth of micro-organisms.The raw potato pieces are first blanched in a heated infusion solutioncontaining one or more sugars and sodium chloride to infuse sugar andsodium chloride into the potato pieces. The potato pieces are dried bysubjecting the pieces to heat for a sufficient time and temperature toreduce the water activity of the pieces to below 0.85. These potatopieces can be stored in ambient room temperatures and don't require anyspecial packaging. The water activity below 0.85 along with high sodiumand sugar concentration renders a final product which lacks desiredcharacteristics both from a texture and taste point.

U.S. Published Patent Application No. US-2015/0010691 describes achemical preservation methodology. It is based on a preservativesolution comprising of water, sodium chloride, citric acid, ascorbicacid, calcium chloride, sodium acid phyrophosphate, potassium sorbateand a protein based composition and applying the preservative solutionto fresh cut potatoes. These products need to be kept underrefrigeration for the period of their shelf life.

EP 0811323 describes another chemical preservation technology that usesthe application of an aqueous solution in which a combination of twoantioxidizing agents participate, specifically potassium metabisulfiteand sodium disulfite, as well as a humidifying agent, specificallysorbitol, and a synergetic agent, specifically ascorbic D.L. acid,wherein prior to immersing the peeled potatoes in said aqueous solutionthere exists an intermediate humidification phase consisting of a waterbath lasting for a period of approximately 30 minutes. The final productcan be stored under refrigeration for 21 days.

Another method has been performed using SCCO₂ with ethanol as aprocessing aid (co-solvent) for the dehydration of Carrots (Fryer,Norton, bakalis, & bridson, 2007). The method describes a batch typesystem with continuous CO₂ flow mechanism operating at definite processparameters (200 Bar; 60° C.). During the process the product is placedwithout a pre-package into the high pressure chamber. According to theresearch, the texture of the product is better than the air driedproducts but not as good as its freeze-dried counterpart. This processis highly time consuming and it removes volatile compounds, resulting inflavor and color loss in the final product. It also states the processof SCCO₂ drying to be zero order and air-drying to be a first orderprocess which is not true in this research.

Other related research publications show that inactivation of microbialand enzymatic activity can be accomplished by treatment with SCCO₂(Wimmer & Zarevucka, 2010) which is also a batch type system. U.S. Pat.No. 7,108,832 describes the application of SCCO₂ for the sterilizationof thermally or hydrolytically sensitive, medically-important materialsincluding biodegradable and other medical polymers, tissue forimplantation or transplantation, medical equipment, drugs and drugdelivery systems. The product is processed in a system with anon-continuous CO₂ flow mechanism.

Similar is U.S. Published Patent Application No. US-2012/0288614 A1,which uses supercritical carbon dioxide to achieve inactivation of thecertain micro-organisms and enzymes in liquid, semi-solid and solidfoods within a batch type apparatus with a non-continuous CO₂ operation.The operating temperature during the process is 40° C. wherein theproduct is packaged in a gas permeable bag (breathable) and is placedinside the pressure vessel. The vessel is pressurized to get the carbondioxide to supercritical state and the product is exposed to thesupercritical carbon dioxide for various time periods after which it isslowly depressurized to avoid the breakdown of the cellular structure ofthe product.

The present invention is directed to overcoming these and otherdeficiencies in the art.

SUMMARY OF THE INVENTION

The present disclosure relates to, inter alia, processes for improvingshelf-life and flavoring of fresh-cut/fresh vegetables, as well as foodproducts produced by these processes. The present disclosure furtherrelates to methods of preparing edible food products and the foodproducts produced by these methods.

In one aspect, the present disclosure provides a process for improvingshelf-life of fresh-cut vegetables that involves the steps generallydescribed below (referred to herein generally as “Process A”). First,this process involves blanching unprocessed vegetable material thatincludes freshly cut vegetables. The blanching increases cell structurepermeability of the freshly cut vegetables. This step yields a blanchedvegetable preparation that is enhanced for accelerated moisture removalvia a supercritical fluids procedure. Second, this process involvessubjecting the blanched vegetable preparation to a first supercriticalfluids procedure to remove a first percentage of moisture therefrom. Thefirst supercritical fluids procedure is performed with a processing aid,thereby yielding an intermediate processed vegetable product infusedwith the processing aid. Third, this process involves performing asecond supercritical fluids procedure to the intermediate processedvegetable product to remove a second percentage of moisture therefrom.The second supercritical fluids procedure is performed without theprocessing aid, thereby yielding a final processed vegetable producthaving improved shelf-life compared to that of the unprocessed vegetablematerial.

In another aspect, the present disclosure also provides a food productthat includes the final processed vegetable product prepared by ProcessA and related embodiments thereof.

In a further aspect, the present disclosure provides a method ofpreparing an edible food product that includes the steps describedbelow. First, this method involves performing Process A or relatedembodiments thereof to yield the final processed vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial. Second, this method involves processing the final processedvegetable product using culinary techniques that can include, withoutlimitation, boiling, frying, baking, toasting, microwaving, and thelike. A food product produced according to this method is also providedby the present disclosure.

In one aspect, the present disclosure provides a process for improvingshelf-life of fresh-cut vegetables that involves the steps generallydescribed below (referred to herein generally as “Process B”). First,this process involves blanching unprocessed vegetable material thatincludes freshly cut vegetables, where the blanching increases cellstructure permeability of the freshly cut vegetables. This step yields ablanched vegetable preparation that is enhanced for infusion of aprocessing aid within the cell structure of the freshly cut vegetablesvia a supercritical fluids procedure. Second, this process involvespackaging the blanched vegetable preparation in a sealed gaspermeable/breathable container with a defined volume of 0.001% or aboveof one or more processing aid. Third, this process involves subjectingthe blanched vegetable preparation within the sealed gaspermeable/breathable container to a supercritical fluids procedure at orabove supercritical temperatures and pressures, thereby yielding apressurized blanched vegetable preparation contained in the gaspermeable/breathable container. Fourth, this process involvesdepressurizing the pressurized blanched vegetable preparation quickly toconvert the supercritical fluids to a gas phase followed by a slowdepressurization stage, thereby yielding a final vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial.

In another aspect, the present disclosure also provides a food productthat includes the final processed vegetable product prepared by ProcessB and related embodiments thereof.

In a further aspect, the present disclosure provides a method ofpreparing an edible food product that includes the steps describedbelow. First, this method involves performing Process B or relatedembodiments thereof to yield the final processed vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial. Second, this method involves processing the final processedvegetable product using culinary techniques that can include, withoutlimitation, boiling, frying, baking, toasting, microwaving, and thelike. A food product produced according to this method is also providedby the present disclosure.

In one aspect, the present disclosure provides a process for improvingshelf-life of fresh-cut vegetables that involves the steps generallydescribed below (referred to herein generally as “Process C”). First,this process involves performing Process A or related embodimentsthereof to yield a first final processed vegetable product. Second, thisprocess involves packaging the first final processed vegetable productin a sealed breathable film bag with a defined volume of one or moreco-solvent. Third, this process involves subjecting the first finalprocessed vegetable product within the sealed breathable film bag to athird supercritical fluids procedure along with temperature variations,thereby yielding a pressurized first final processed vegetable productcontained in the sealed breathable film bag. Fourth, this processinvolves depressurizing the pressurized first final processed vegetableproduct quickly to convert the supercritical fluids to a gas phasefollowed by a slow depressurization stage, thereby yielding a completedvegetable product having an improved shelf-life compared to theunprocessed vegetable material.

In another aspect, the present disclosure also provides a food productthat includes the completed vegetable product prepared by Process C andrelated embodiments thereof.

In a further aspect, the present disclosure provides a method ofpreparing an edible food product that includes the steps describedbelow. First, this method involves performing Process C or relatedembodiments thereof to yield the completed vegetable product having animproved shelf-life compared to the unprocessed vegetable material.Second, this method involves processing the completed vegetable productusing culinary techniques that can include, without limitation, boiling,frying, baking, toasting, microwaving, and the like. A food productproduced according to this method is also provided by the presentdisclosure.

The processes of the present disclosure have the unique ability toreduce both the water activity and the pH within the fresh-cut vegetableproduct. Such a combination makes the resulting food productshelf-stable without requiring refrigerated or frozen storageconditions. The fresh-cut vegetable products can be made from vegetablessuch as sweet potato, yam, artichoke, radish, carrot, turnip, beetroots, other root vegetables, as well as other non-root/tubervegetables.

Some advantages of the processes of the present disclosure include, forexample, processes for making the vegetable product more convenient thancurrently available fresh produce or frozen/canned products. Anotheradvantage is that the processes of the present disclosure allow for theproduction of healthier food products than the currently available freshproduce or frozen/canned produce by reducing the time and temperaturerequired for cooking/frying/baking. Another advantage of the processesof the present disclosure is the development of alternative shelf-lifeextension methods for fresh-cut vegetables to the existing methods ofdehydrating, chemical treatments, freezing and canning.

In one embodiment of the processes for improving shelf-life of fresh-cutvegetables, the present disclosure provides a process that involves acombination of blanching, air-drying (optional), and supercritical CO₂(SCCO₂) treatment, with and then without processing aid (co-solvent), offresh-cut vegetables for extension of their shelf life at roomtemperature and even a longer shelf life under refrigerated conditions.The fresh-cut and/or peeled vegetables are blanched, partly air-dried(optional) and then treated with the SCCO₂ containing processing aid(co-solvent). Subsequently, SCCO₂ treatment may continue without anyprocessing aid (co-solvent) to remove any residual processing aid(co-solvent) from the product.

These and other objects, features, and advantages of this invention willbecome apparent from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating aspects of the present invention, thereare depicted in the drawings certain embodiments of the invention.However, the invention is not limited to the precise arrangements andinstrumentalities of the embodiments depicted in the drawings. Further,if provided, like reference numerals contained in the drawings are meantto identify similar or identical elements.

FIG. 1A is a schematic of a process flow diagram of one embodiment of aprocess for improving shelf-life of fresh-cut vegetables according tothe present disclosure.

FIG. 1B is a schematic of a process flow diagram of another embodimentof a process for improving shelf-life of fresh-cut vegetables accordingto the present disclosure.

FIG. 2 is a graph illustrating moisture content versus drying time fordifferent methods for preparing potato.

FIG. 3A is a graph showing the comparison for drying rate and shrinkagebetween an air-drying process and a process according to the presentinvention for potato. The arrows indicate which X and Y axis apply.Hybrid process refers to the process of the present disclosure.

FIG. 3B is a graph showing the comparison for drying rate and shrinkagebetween the air-drying process and a process according to the presentinvention for sweet-potato. Hybrid process refers to the process of thepresent disclosure.

DESCRIPTION OF THE INVENTION

The present disclosure provides various processes for improvingshelf-life of fresh-cut vegetables. As used herein, “improvingshelf-life” refers to an improvement of the shelf-life at roomtemperature of the vegetable, and an even longer improvement of itsshelf-life when stored under refrigerated conditions. One mechanism bywhich the shelf-life of the vegetables is improved is due to the removalof moisture from the vegetables, which in turn decreases the wateractivity (A_(w)) thereof. The improvement of shelf-life can also includeremoval of moisture and the reduction of pH and water activity, while atthe same time minimizing shrinkage.

Suitable vegetables for use in the processes of the present inventioncan include all vegetable. For example, suitable vegetables for use inthe processes of the present invention can include, without limitation,potato, sweet potato, yam, artichoke, radish, carrot, turnip, beetroots, other root vegetables, and other non-root/tuber vegetables.

As used herein, the term “fresh-cut vegetables” refers to vegetablesthat are cut into portions or pieces prior to undergoing any processing(e.g., heating, freezing, canning, and chemical treatments) that wouldalter their cell structure in a significant manner as compared to theircell structure at the time of harvest. The vegetables may be cut intoportions or pieces within about 60 minutes or less prior to beingsubjected to blanching, as described herein. The vegetables can be cutin any manner suitable for the type of vegetable. For example, potatoescan be cut into pieces suitable for standard French fries, tater tots,scalloped potatoes, etc. For vegetables that naturally have outer skins(e.g., potatoes), they can be used in the processes of the presentinvention with or without their peelings. For example, when using apotato in the process, the fresh-cut potato can be used with or withoutits peel.

As used herein, the term “blanching” generally refers to a process ofcooking freshly cut vegetables in water at an elevated temperature for adesired period of time in order to increase the permeability within thecellular and to inactivate the surface enzymatic activity. In oneembodiment, the blanching is conducted at a temperature of between about65-90° C. for at least 5 minutes, at least 10 minutes, at least 15minutes, at least 20 minutes, at least 25 minutes, at least 30 minutes,at least 35 minutes, and so forth, up to a maximum 120 minutes.

As used herein, the term “supercritical fluids procedures” generallyrefers to a process of subjecting a vegetable material to supercriticalfluids in order to infuse/impregnate the said product with processingaids to either reduce the equilibrium pH of the product, enhance theorganoleptic properties, or/and to remove moisture from the productwithout resulting in shrinkage thus reducing the water activity.Suitable supercritical fluids for use in the process of the presentdisclosure can include, without limitation, carbon dioxide, nitrousoxide, ethanol, propane, ethylene, acetone, and the like.

As used herein, a “supercritical pressure” for a substance (e.g.,compound, composition, etc.) includes pressures having a value abovethat substance's critical pressure.

As used herein, a “supercritical temperature” for a substance (e.g.,compound, composition, etc.) includes temperatures above thatsubstance's critical temperature.

As used herein, when a substance (e.g., compound, composition, etc.) issubjected to a pressure and a temperature higher than its criticalpressure and temperature point, the fluid is said to be “supercritical.”

As used herein, the term “processing aid” refers to co-solvent that isused in a supercritical fluids procedure in order to infuse/impregnatethe vegetable product with either one or a combination of variousprocessing aids to either enhance the organoleptic properties or/and toremove moisture from the product without resulting in shrinkage thusreducing the water activity. Suitable processing aids can include,without limitation, co-solvents such as ethanol, distilled watervinegar, vinegar, lemon juice, lemon juice concentrate, apple juice,apple juice concentrate, cumin seed, ginger, garlic, lactic acid,gluconic acid, malic acid, peroxyacetic acid, tartaric acid, acetic acidand its derivatives, sodium bisulfate, gluconodeltalactone (GDL), citricacid, buffers of such acids, oleoresins, and the like.

As used herein, the term “reducing co-solvent” refers to any co-solventthat can be added to the vegetable material during the processes of thepresent invention in order to decrease the pH equilibrium thereof.Suitable reducing co-solvents can include, without limitation, ethanol,distilled water vinegar, vinegar, lemon juice, lemon juice concentrate,apple juice, apple juice concentrate, cumin seed, ginger, garlic, lacticacid, gluconic acid, malic acid, peroxyacetic acid, tartaric acid,acetic acid and its derivatives, sodium bisulfate, gluconodeltalactone(GDL), citric acid, buffers of such acids, oleoresins, and the like.

The processes of the present disclosure combine various processing stepsin a unique way in order to achieve more efficient end results. Theprocess of blanching allows the cell membrane to become more permeable.This augments the removal of water during air drying as the water findsit easier to migrate to the surface. Once the surface moisture has beenremoved with the help of air drying, the remaining internal moistureneeds to be taken out with minimum deterioration within the cellularstructure of the vegetable product. Due to the porous cell structure andsurface moisture already removed, the penetration of the modifiedsupercritical fluid (i.e., along with the co-solvent) within the cellstructure becomes easier, thus more water present within the internalcellular structure can be displaced from the product with minimumshrinkage of the product. Within the process, the supercritical fluidacts as a transportation medium that can solubilize the processing aidand transport it to the internal cellular structure which otherwise isefficiently not possible. This solubilized processing aid can nowinteract with the free water molecules within the cellular structure toform bonds and thus, together can be carried out by the transportationmedium, the supercritical fluid, without destroying the cell walls thatcould otherwise result into shrinkage. This processing style allows forthe uniform removal of the moisture from the entire cross section of theproduct thus resulting in the lowered A_(w), water activity of 0.93 orbelow, which inhibits the growth of various micro-organisms of concernto food safety, without adversely affecting the final texture and tasteof end product.

Similarly, during the static processing technique, due to morepermeability within the cell structure of the product, the supercriticalfluid as a transportation medium can solubilize the processing aid andtransport it to the internal cellular structure to deposit theprocessing aid there, which is otherwise not efficiently possible. Theprocessing technique accounts for a swift depressurization step tochange the state of the fluid (transportation medium) from supercriticalto gas phase that augments the rate of deposition. This results in moreinfusion or impregnation of the processing aid (co-solvent), thusallowing the reduction of the equilibrium pH very swiftly. Also, moreinfusion of various essential oils within the cell structure of theproduct allows for better anti-microbial properties. The uniformdeposition of the processing aid renders a lowered equilibrium pH of 4.6or below, which inhibits the growth of various micro-organisms ofconcern to food safety, without adversely affecting the final textureand taste of the end product. This methodology allows for the usage ofmuch diluted processing aid solutions to get to the equilibrium pH of4.6 and below, which is otherwise not possible with any other technique.The end product developed from the current technique has a crispiertexture as the processing aid being acidic, inhibits the breakdown ofthe pectin within the cell wall. And eventually the end product holdsits texture better and also has a lower cook time due to lower moistureand softer tissue of the end vegetable product. This also results inmore than 30% less oil uptake in the product which are fried in oil.

I. Process A: Improving Shelf-Life of Fresh-Cut Vegetables

In one aspect, the present disclosure provides a process for improvingshelf-life of fresh-cut vegetables that involves the following steps:(i) blanching unprocessed vegetable material that includes freshly cutvegetables, where the blanching increases cell structure permeability ofthe freshly cut vegetables, thereby yielding a blanched vegetablepreparation that is enhanced for accelerated moisture removal via asupercritical fluids procedure; (ii) subjecting the blanched vegetablepreparation to a first supercritical fluids procedure to remove a firstpercentage of moisture therefrom, where the first supercritical fluidsprocedure is performed with a processing aid, thereby yielding anintermediate processed vegetable product infused with the processingaid; and (iii) performing a second supercritical fluids procedure to theintermediate processed vegetable product to remove a second percentageof moisture therefrom, where the second supercritical fluids procedureis performed without the processing aid, thereby yielding a finalprocessed vegetable product having improved shelf-life compared to thatof the unprocessed vegetable material.

In accordance with this process, the improved shelf-life of the finalprocessed vegetable product corresponds to a water activity (A_(w)) ofbelow 0.93. In one embodiment, the water activity (A_(w)) is betweenabout 0.6 and about 0.93.

In accordance with this process, the percentage of moisture removed fromthe unprocessed vegetable material upon completion of the process isbetween about 1-80 percent.

In accordance with this process, the first percentage of moistureremoved is at least 1 percent.

In accordance with this process, the second percentage of moistureremoved is at least 0.5 percent.

In one embodiment, the blanching is conducted at a temperature ofbetween about 65-90° C. for at least 5 minutes, at least 10 minutes, atleast 15 minutes, at least 20 minutes, at least 25 minutes, at least 30minutes, at least 35 minutes, and so forth, up to a maximum of 120minutes.

In one embodiment with this process, when the freshly cut vegetableshave an outer skin that can be peeled, the blanching step is performedwith the freshly cut vegetables with and/or without the peel.

In one embodiment of this process, the first supercritical fluidsprocedure is carried out at or above supercritical pressures andtemperatures and at a fluids flow rate at or above 1 liter/minute toprovide a residence time of 10 seconds or above with 2 percent or moreof the processing aid of the total mass of freshly cut vegetables for 1minute or more.

In one embodiment of this process, the second supercritical fluidsprocedure is carried out at or above supercritical pressures andtemperatures and at a fluids flow rate at or above 1 liter/minute toprovide a residence time of 10 seconds or above in absence of theprocessing aid for 1 minute or more.

In one embodiment of this process, the first supercritical fluidsprocedure and the second supercritical fluids procedure are carried outunder continuous flow. For example, when product is placed in the basketand when this basket is placed in the chamber, then the chamber isclosed and the system is equilibrated with the supercritical fluid fromthe source to 750 psi. Once this is done, then the pump is turned on tofurther pressurize the chamber at or above the critical point so thatthe fluid is in the supercritical state. During this step, thesupercritical fluid enters the chamber along with the processing aid,which is introduced via a separate pump into the chamber. Once the fluidand the processing aid come together, then the supercritical fluidsolubilizes the processing aid within itself and interacts with thevegetable product to infuse the processing aid (co-solvent) into thecellular structure. The processing aid is introduced at a defined flowrate to get 2% or more of processing aid of total volume of vegetableproduct into the chamber in the entire duration of the processing runtime. Once the required pressure and temperature are attained inside thechamber, then the supercritical fluid is allowed to flow at a certainrate of 1 liter/minute or above through the chamber along with theprocessing aid. This processing style has been termed as a continuousflow, wherein the supercritical fluid flows continuously through thechamber at a certain flow rate which results in the continuous removalof water/moisture from the product. Once the first half of the moistureis removed from the product then the flow of the processing aid isstopped. And the second supercritical fluid procedure is applied for acontrolled period of time without the processing aid to help remove theadditional half of the moisture along with the extra amount of theprocessing aid (co-solvent) which could potentially adversely affect thetaste profile of the end product.

In one embodiment, this process further includes a step of air-dryingthe blanched vegetable preparation prior to subjecting it to the firstsupercritical fluids procedure, thereby facilitating moisture removalfrom the blanched vegetable preparation during the first supercriticalfluids procedure. In a particular embodiment, the air-drying stepincludes drying at about 50-250° C. for 1 minute or above (i.e., up toabout 45 minutes).

In one embodiment, this process further includes the step of reducingequilibrium pH of the final processed vegetable product by contacting itwith one or a combination of pH reducing co-solvents. In a particularembodiment, the equilibrium pH of the final processed vegetable productis reduced to below 4.6, and as low as about 3.0.

In another aspect, the present disclosure also provides a food productthat includes the final processed vegetable product prepared by thisprocess.

In a further aspect, the present disclosure provides a method ofpreparing an edible food product that includes the steps of: (i)performing this process to yield the final processed vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial; and (ii) processing the final processed vegetable productusing culinary techniques that can include, without limitation, boiling,frying, baking, toasting, microwaving, and the like. A food productproduced according to this method is also provided by the presentdisclosure.

II. Process B: Improving Shelf-Life of Fresh-Cut Vegetables

In one aspect, the present disclosure provides a process for improvingshelf-life of fresh-cut vegetables that includes the steps of: (i)blanching unprocessed vegetable material that includes freshly cutvegetables, where the blanching increases cell structure permeability ofthe freshly cut vegetables, thereby yielding a blanched vegetablepreparation that is enhanced for infusion of a processing aid within thecell structure of the freshly cut vegetables via a supercritical fluidsprocedure; (ii) packaging the blanched vegetable preparation in a sealedgas permeable/breathable container with a defined volume of 0.001% orabove of one or more processing aid; (iii) subjecting the blanchedvegetable preparation within the sealed gas permeable/breathablecontainer to a supercritical fluids procedure at or above supercriticaltemperatures and pressures, thereby yielding a pressurized blanchedvegetable preparation contained in the gas permeable/breathablecontainer; and (iv) depressurizing the pressurized blanched vegetablepreparation quickly to convert the supercritical fluids to a gas phasefollowed by a slow depressurization stage, thereby yielding a finalvegetable product having an improved shelf-life compared to theunprocessed vegetable material.

In one embodiment, the blanching is conducted at a temperature ofbetween about 65-90° C. for at least 5 minutes, at least 10 minutes, atleast 15 minutes, at least 20 minutes, at least 25 minutes, at least 30minutes, at least 35 minutes, and so forth, up to a maximum of 120minutes.

In accordance with this process, the step of packaging the blanchedvegetable preparation in a sealed gas permeable/breathable container isperformed with a defined volume of 0.001% or above of one or moreprocessing aid. As used herein, a “gas permeable/breathable container”refers to any container, bag, or pouch that has a breathable film or aporous membrane or a perforated film membrane. Suitable examples of gaspermeable/breathable containers for use in this process can include,without limitation, TYVEK® pouches, header bags with TYVEK® stripsattached, perforated plastic bags/pouches, perforated paper basedbags/pouches. The method of sealing the gas permeable/breathablecontainer can involve the standard methods and techniques to seal suchcontainer (e.g., heat sealing, hand crimping). The defined volume of theone or more processing aid can be between 0.001% to about 30%.

In accordance with this process, the step of subjecting the blanchedvegetable preparation within the sealed gas permeable/breathablecontainer to a supercritical fluids procedure at or above supercriticaltemperatures and pressures to remove a percentage of moisture therefromcan be performed as noted below. For example, in one embodiment,packaging the blanched vegetable is done in the breathable bag, and thenadding the processing aid (co-solvent) to the bag followed by heatsealing the bag. The bag may or may not be flipped upside down to allowfor the processing aid to mix with the vegetable product. Thereafter,the sealed bags are placed in the perforated basket, which is furtherplaced into the chamber. After the basket is in the chamber, then thechamber is closed and the system is equilibrated with the supercriticalfluid from the source to 750 psi. Once this is done, then the pump isturned on to further pressurize the chamber at or above the criticalpoint so that the fluid is in the supercritical state. During this step,as the supercritical fluid enters the chamber, it simultaneously entersinside the bags via the breathable portion of the bag and interacts withthe processing aid to solubilize it within itself and interact with thevegetable product to infuse the processing aid (co-solvent) into thecellular structure. The processing aid can also be introduced via aseparate pump in to the chamber at a defined flow rate to get 2% or moreof processing aid of total volume of vegetable product into the chamberin the entire duration of the processing run time. Once the requiredpressure and temperature are attained inside the chamber and the bag,then the product is left to sit within the chamber for sometime to letthe modified supercritical fluid (i.e., with the processing aid) infuseinto the vegetable product and equilibrate itself uniformly within thevegetable product. After which, the system is quickly depressurized tochange the phase of the fluid from supercritical to gas phase, which isthen followed by slow depressurization. This step of swiftdepressurization allows the state of the fluid to change which resultsin the separation of the processing aid from the fluid as the processingaid cannot remain solubilized in the gas phase of the fluid; therefore,this step results in the deposition of the processing aid within thecellular structure of the vegetable product.

As used herein, “pressurized” means a pressure above the criticalpressure of the fluid.

In accordance with this process, the step of depressurizing thepressurized blanched vegetable preparation is done quickly to convertthe supercritical fluids to a gas phase followed by a slowdepressurization stage, thereby yielding a final vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial. As used herein, “quickly” refers to a faster rate ofdepressurization which results in the sudden drop of the pressure offluid below its critical point thus allowing the fluid to covert fromsupercritical to gas phase. In accordance with this process, the “slowdepressurization stage” is defined as a slower rate of depressurizationwhich does not impair the integrity of the bag or the vegetable inside.

In one embodiment, this process further includes a step of air-dryingthe blanched vegetable preparation prior to subjecting it to thesupercritical fluids procedure, thereby facilitating moisture removalfrom the blanched vegetable preparation during the supercritical fluidsprocedure. In a particular embodiment, the air-drying step includesdrying at about 50-250° C. for 1 minute or above (i.e., up to about 45minutes).

In one embodiment, this process further includes the step of reducingequilibrium pH of the final processed vegetable product by contacting itwith a reducing co-solvent. In a particular embodiment, the equilibriumpH of the final processed vegetable product is reduced to below 4.6, andas low as about 3.0.

In one embodiment of this process, the supercritical fluids procedure iscarried out at no-flow conditions (0 liters/minute).

In one embodiment of this process, when the freshly cut vegetables havean outer skin that can be peeled, the blanching step is performed withthe freshly cut vegetables with and/or without the peel.

In another aspect, the present disclosure also provides a food productthat includes the final processed vegetable product prepared by thisprocess.

In a further aspect, the present disclosure provides a method ofpreparing an edible food product that includes the steps of: (i)performing this process to yield the final processed vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial; and (ii) processing the final processed vegetable productusing culinary techniques that can include, without limitation, boiling,frying, baking, toasting, microwaving, and the like. A food productproduced according to this method is also provided by the presentdisclosure.

III. Process C: Improving Shelf-Life of Fresh-Cut Vegetables

In one aspect, the present disclosure provides a process for improvingshelf-life of fresh-cut vegetables that includes the steps of: (i)performing Process A as described herein to yield a first finalprocessed vegetable product; (ii) packaging the first final processedvegetable product in a sealed breathable film bag with a defined volumeof one or more co-solvent; (iii) subjecting the first final processedvegetable product within the sealed breathable film bag to a thirdsupercritical fluids procedure along with temperature variations,thereby yielding a pressurized first final processed vegetable productcontained in the sealed breathable film bag; and (iv) depressurizing thepressurized first final processed vegetable product quickly to convertthe supercritical fluids to a gas phase followed by a slowdepressurization stage, thereby yielding a completed vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial.

As used herein, a “gas permeable/breathable container” refers to anycontainer, bag, or pouch that has a breathable film or a porous membraneor a perforated film membrane. Suitable examples of gaspermeable/breathable containers for use in this process can include,without limitation, TYVEK® pouches, header bags with TYVEK® stripsattached, perforated plastic bags/pouches, perforated paper basedbags/pouches, and the like. The method of sealing the gaspermeable/breathable container can involve the standard methods andtechniques to seal such container (e.g., heat sealing). The definedvolume of the one or more processing aid can be between about 0.001% toabout 30%

In accordance with this process, the third supercritical fluidsprocedure (along with temperature variations) can include the steps ofprocessing the vegetable product with the steps described for Process A,herein, followed by packaging the product into breathable bags/pouchesand also introducing the defined quantity of the processing aid(co-solvents). The bags would then be heat sealed and placed in thebaskets which are then placed in the chamber and the system ispressurized. Once the system reaches the required pressure andtemperature within the supercritical state, then the product is let tosit within the chamber for a time sufficient to let the processing aidinfuse into the vegetable product with the help of the transportationmedium, which is the supercritical fluid, and equilibrate itselfuniformly within the vegetable product. Thereafter, the system isquickly depressurized to change the phase of the fluid fromsupercritical to gas phase, which is then followed by slowdepressurization. This step of swift depressurization allows the stateof the fluid to change, which results in the separation of theprocessing aid from the fluid as the processing aid cannot remainsolubilized in the gas phase of the fluid; therefore, this step resultsin the deposition of the processing aid within the cellular structure ofthe vegetable product. This third supercritical fluids procedure isperformed so as to yield a pressurized first final processed vegetableproduct contained in the sealed breathable film bag. As used herein,“pressurized” means a pressure of at or above the critical point.

In accordance with this process, the step of depressurizing thepressurized first final processed vegetable product is done quickly toconvert the supercritical fluids to a gas phase followed by a slowdepressurization stage, thereby yielding a completed vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial. As used herein, “quickly” refers to a faster rate ofdepressurization which results in the sudden drop of the pressure offluid below its critical point thus allowing the fluid to covert fromsupercritical to gas phase. In accordance with this process, the “slowdepressurization stage” is defined as a slower rate of depressurizationwhich does not impair the integrity of the bag or the vegetable inside.In another aspect, the present disclosure also provides a food productthat includes the completed vegetable product prepared by this process.

In a further aspect, the present disclosure provides a method ofpreparing an edible food product that includes the steps of: (i)performing this process to yield the final processed vegetable producthaving an improved shelf-life compared to the unprocessed vegetablematerial; and (ii) processing the completed vegetable product usingculinary techniques that can include, without limitation, boiling,frying, baking, toasting, microwaving, and the like. A food productproduced according to this method is also provided by the presentdisclosure.

All numeric ranges are inclusive of narrower ranges; delineated upperand lower range limits are interchangeable to create further ranges notexplicitly delineated.

IV. Additional Embodiments of a Process for Improving Shelf-Life ofFresh-Cut Vegetables

Additional embodiments of a process for improving shelf-life offresh-cut/fresh vegetables are disclosed. In one aspect, a new processhas been developed which is a combination of blanching, air-drying(optional), and supercritical CO₂ (SCCO₂) treatment, with and thenwithout a processing aid (co-solvent) of fresh-cut vegetables forextension of their shelf life at room temperature and even a longershelf life under refrigerated conditions. The processing aids(co-solvents) are polar or non-polar solvents such as ethanol, vinegar,apple juice concentrate, lactic acid, gluconodeltalactone, oleoresinsand other materials which are mixed with supercritical CO₂.

One example of the process would be its application to remove moisturefrom the product to achieve a lower water activity (A_(w)) by includingthe step of blanching of the fresh-cut and/or peeled vegetables,followed by partial air-drying (optional) and then treatment with theSCCO₂ containing ethanol. Subsequently, SCCO₂ treatment continueswithout any ethanol addition to remove any residual ethanol from theproduct.

The other example of the process would include the step of blanching,followed by partial air drying (optional), then the treatment with SCCO₂with a polar acidic processing aid (co-solvent) formulations such as 5%distilled water vinegar or apple juice concentrate with lemon juiceconcentrate and garlic to infuse the acid in the cellular structure toattain lower equilibrium pH by manipulating the temperature of thecarbon dioxide during process to change the solubility of the CO₂followed by quick decrease in the pressure to change the state of thesupercritical CO₂ to gas phase.

Another example of the process would include the step of blanching,followed by partial drying (optional), then the treatment with SCCO₂with an essential oil like citral and eugenol to impregnate theprocessing aid (co-solvent) into the cellular structure of the productby manipulating the temperature of the carbon dioxide during process tochange the solubility of the CO₂ followed by quick decrease in thepressure to change the state of the supercritical CO₂ to gas phase.

In one aspect, the present invention relates to a process for improvingshelf-life of fresh-cut vegetables, said process comprising the stepsof: (i) blanching freshly cut vegetables (with or without peel) to yielda blanched vegetable preparation; (ii) subjecting the blanched vegetablepreparation to a first supercritical CO₂ procedure to remove apercentage of moisture (5% and or above) therefrom, wherein the firstsupercritical CO₂ procedure is performed with ethanol; and (iii)performing a second supercritical CO₂ procedure to the blanchedvegetable preparation to remove a further percentage of moisture (5% andor above) therefrom, wherein the second supercritical CO₂ procedure isperformed without ethanol.

In one embodiment of the process, the blanching is conducted at about45-90° C. for about 5-30 minutes.

In one embodiment of the process, the first supercritical CO₂ procedureis carried out at a pressure of about 150-400 bar, a temperature ofabout 35-130° C., and a CO₂ flow rate of about 1-100 L/minute in adynamic CO₂ operation or a static CO₂ operation to provide a residencetime of 10 seconds to 20 minutes with 2-8 mol % of processing aid(co-solvent) for about 5-120 minutes.

In one embodiment of the process, the second supercritical CO₂ procedureis carried out at a pressure of about 150-350 bar, a temperature ofabout 35-130° C., and a CO₂ flow rate of about 1-100 L/minute in adynamic CO₂ operation or a static CO₂ operation to provide a residencetime of 10 seconds to 20 minute in the absence of ethanol for about5-120 minutes.

In one embodiment of the process, the first supercritical CO₂ procedureand second supercritical CO₂ procedure are carried out under continuousor non-continuous flow.

In one embodiment, the process further comprises air drying the blanchedvegetable preparation prior to subjecting it to the first supercriticalCO₂ procedure. In a particular embodiment of the process, the air dryingstep comprises drying at about 50-100° C. for about 10-25 minutes.

In one embodiment, the process comprises infusion/impregnation ofsoluble compounds into the blanched vegetable preparation.

In one embodiment of the process, the supercritical CO₂ is carried outat a pressure of about 150-350 bar, a temperature of about 35-130° C.,and the CO₂ flow is static to provide a residence time of 1-20 minutes.

In one embodiment of the process, the pre-cut vegetables are packaged,wherein the packaging consists of gas permeable/breathable material.

In one embodiment of the process, the soluble solvents (solid or liquid)are placed in the same packaging as the vegetable or are placedseparately into the chamber during the process.

In one embodiment of the process, the temperature of the carbon dioxideis manipulated to change the solubility of the carbon dioxide during theprocess and similarly the pressure is changed during the process tochange the state of carbon dioxide between supercritical and gas phase.

The process of the present invention is effective to reduce theequilibrium pH of the low acid vegetable products below 4.6 within thedefined run time (30 seconds and above).

The process of the present invention is effective to reduce theenzymatic activity in pre-cut vegetables upwards of 95%.

The process of the present invention can be used to process anyvegetable, including, without limitation, vegetables such as sweetpotato, yam, artichoke, radish, carrot, turnip, beet roots, other rootvegetables, and other non-root/tuber vegetables.

The process of the present invention is effective to remove about 30-50%of moisture from fresh-cut vegetables.

In another aspect, the present invention relates to a food productcomprising vegetables prepared by a process according to the presentdisclosure.

In another aspect, the present invention relates to a method ofpreparing an edible food product, said method comprising: (i) performingthe process according to the present disclosure so as to yield avegetable product having an improved shelf-life with a lower A_(w)(water activity) below 0.93; and (ii) processing the vegetable productusing culinary techniques selected from the group consisting of boiling,frying, baking, toasting, microwaving, and the like. In another aspect,the present invention relates a food product produced according to thismethod.

EXAMPLES

The following examples are intended to illustrate particular embodimentsof the present invention, but are by no means intended to limit thescope of the present invention.

Example 1 Shelf-Life Extension Using Supercritical CO₂

One embodiment of a process of the present disclosure is illustrated inthe process flow diagram of FIG. 1A. As shown in FIG. 1A, the processcan include the use of supercritical CO₂ and the following steps:blanching, air drying (optional), supercritical CO₂ (with a co-solvent),de-pressurization, supercritical CO₂ (without a co-solvent),de-pressurization, and packaging. Alternatively, as shown in FIG. 1A,this embodiment can include packaging of the vegetables after the airdrying step and before the supercritical CO₂ (with co-solvent) step.

Another embodiment of a process of the present disclosure is illustratedin the process flow diagram of FIG. 1B. As shown in FIG. 1B, the processcan include the use of supercritical CO₂ and the following steps:blanching, air drying (optional), supercritical CO₂ (with ethanol as theco-solvent), de-pressurization, supercritical CO2 (without the ethanolco-solvent), de-pressurization, and vacuum packaging. Alternatively, asshown in FIG. 1B, this embodiment can include addition of volatileflavor after the supercritical CO2 (without ethanol) step,de-pressurization, and then the vacuum packaging.

In one embodiment of the process of the present disclosure, the processcan involve the following combination of steps: (i) blanching freshlycut vegetables (with or without peel) at 45-90° C. for 5-30 minutes;(ii) optionally, partially air drying the blanched peeled and cutvegetables at 50-100° C. for 10-25 minutes; (iii) next, processing withhigh pressure SCCO₂ containing processing aid (co-solvent) (pressure:150-350 Bar; temperature: 35-130° C.; CO₂ flow rate: 1-100 L/minute in adynamic operation to provide a residence time of 10 seconds to 20minute; processing aid (co-solvent) flow rate: 2-8 mol % of the CO₂ flowrate.) for a period of time; and (iv) optionally, processing with theSCCO₂ without processing aid (co-solvent) (pressure: 150-350 Bar;temperature: 35-130° C.; CO₂ flow rate: 1-100 L/minute in a dynamicoperation to provide a residence time of 10 seconds to 20 minute) for aperiod of time.

The high pressure during the process increases the solubility of theSCCO₂ and the higher temperature increases the diffusivity of the CO₂which helps enhance the penetration of the CO₂ (King, Mubarak, & Kim,2005) (Frederick G & Kirkwood, 1930) into the product leading to afaster reduction of the water activity of the product along with areduction of the pH of the product. This process with a polar processingaid (co-solvent) such as ethanol or 5% distilled water vinegar and otheroleoresins also causes an increase in the polarity of the SCCO₂, thusallowing maximum extraction of the cytoplasmic material from anymicroorganisms in the product and thereby achieving longer shelf life.The increase in the polarity also increases the reduction rate of thewater activity by increasing the solubility of the water in thesupercritical CO₂ and causing faster removal of water.

Combining, the blanching and the SCCO₂ with processing aid (co-solvent)treatments synergistically enhances the ability of these individualtreatments to reduce the pH and Aw thus resulting in shelf-stablefresh-cut vegetables. Also, the SCCO₂ treatments combined with theoptional air-drying reduces the water activity with minimum shrinkage.

The uniqueness of the process is achieved through the sequence in whichthe process is performed. The process of blanching allows the cellmembrane to become more porous. This augments the removal of waterduring air drying as the water finds it easier to escape to the surface.Due to this, the penetration of the supercritical carbon dioxide alongwith the processing aid (co-solvent) within the cell structure becomeseasier thus more water present within the cellular can be removed fromthe product with minimum shrinkage of the product. Similarly, due tomore porosity within the cell structure of product, more infusion orimpregnation of the processing aid (co-solvent) such as oleoresins or 5%distilled water vinegar or Apple juice concentrate can happen thusallowing in the reduction of the equilibrium pH swiftly. Also moreinfusion of various essential oils within the cell structure of theproduct allows better anti-microbial properties.

Although air-drying is used as an economical commercial practice formanufacturing dehydrated products, it results in shrunken products ofvery poor quality. On the other hand, use of SCCO₂ results in fasterdrying with minimum shrinkage. The process is, however, not economicallyattractive because of high operating costs. As shown in FIG. 2, FIG. 3A,and FIG. 3B the SCCO₂ rate of drying is not constant during the entireprocess as claimed by Brown et al (2010) and follows the same trend asair drying. It can be seen in FIG. 3A and FIG. 3B, that air-drying ratebecomes slower after 20 minutes and therefore further removal ofmoisture from the product is best achieved through the SCCO₂ process. Asfor the initial removal of moisture from the product, it can be seen inFIG. 2 that for the first 20 minutes the rate of air-drying for blanchedsample is faster than drying with SCCO₂ containing ethanol. Drying withSCCO₂ after blanching is initially slower since SCCO₂ becomes saturatedfaster with the surface moisture and the rate of removal of water bySCCO₂ is reduced. Therefore, as finally shown in FIG. 3A and FIG. 3B,with the application of this new inventive process, minimum shrinkagewith maximum rate of drying can be achieved and make the processcommercially attractive. With the sweet potatoes, rather a faster rateof drying has been observed (shown in FIG. 3B) which makes the processfurther more attractive at commercial scale.

The literature reported prior art methodologies cannot achieve reductionin the equilibrium pH of the solid food products such as the low acidvegetables and fruits inside a packaging. The invention uses thecombination of blanching the fresh cut vegetable in water followed bypackaging the product in a gas permeable bag (breathable) with theprocessing aid (co-solvent)s which are low pH formulations as describedin Table 1. The process of blanching increases the porosity within thecellular structure. Then these packaged products are treated with thesupercritical carbon dioxide wherein, the high pressure allows for thesolubilization of the processing aid (co-solvent) in the SCCO₂ and thechanges in the temperatures during the process allow for the fasterdiffusivity of the solvent and also effect the solubility during theprocess. The residence time in the pressurized chamber allows for theinfusion of the processing aid (co-solvent) inside the cellularstructure of the vegetable via the interaction between the solubilizedprocessing aid (co-solvent)s and the product. After this the pressure isquickly reduced to bring the CO₂ to gas phase from its supercriticalstate. This allows for the separation of the processing aid (co-solvent)from the supercritical CO₂ before all the CO₂ leaves the system, henceresulting in lowering of pH of the product. Finally the system is slowlydepressurized and the processed vegetable product is taken out from thesystem.

Unique Features of the Invention:

Along with the removal of moisture from the product during the process,the moderately high-temperature SCCO₂ treatments partially cooks thestarches which further decreases the time and temperature required forfinal cooking/frying/baking.

For example, performing the combined treatments on the fresh-cutpotatoes and sweet potatoes results in shelf-stable French Fries thatcan be cooked at a lower temperatures of 350° F. (baking or frying) andfor a shorter time-period of 10-15 minutes when baked or 2-5 minuteswhen fried; whereas, frozen potato or sweet potato French fries arerecommended to be cooked at 400-450° F. for 20-30 minutes when baked and5-6 minutes when fried. Unlike the frozen French fries which are prefried before being frozen, the current invention allows for the productto be cooked once ‘for a shorter period of time thus resulting in lessacrylamide formation, a potential carcinogen.

The various processing aids (co-solvents) used in the process include,for example, the following formulations as mentioned in Table 1, below.

TABLE 1 Various Processing Aids (Co-Solvents) and Their Dosage Per 100Gram of Food Product Processing Aid (Co-Solvent) Dosage per 100 Gram ofProduct 200 proof ethanol 4-12 ml 5-6% acidity distilled water 2-8 ml +2-5 ml respectively. vinegar + 100% lemon juice concentrate 5-6% aciditydistilled water 2-8 ml + 2-4 gm + 2-4 gm + vinegar + cumin seed +ginger + 2-4 gm, respectively garlic respectively 5-6% acidity distilledwater vinegar + 2-8 ml + 1-3 ml + 2-4 gm + 100% apple juiceconcentrate + 2-4 gm + 2-4 gm respectively. cumin seed + ginger + garlicrespectively Various Oleoresins 1-4 ml, respectively Lactic Acid 2-8 mlLactic acid + lemon Juice concentrate 2-8 ml + 2-5 ml, respectively.Lactic acid + 5-6% acidity 2-8 ml + 2-5 ml, respectively. distilledwater vinegar 5-6% acidity distilled water vinegar 2-8 ml GDL(Gluconodeltalactone) + 2-8 ml + 2-8 ml, respectively. 5-6% aciditydistilled water vinegar Bisulfates of Soda + 2-8 ml + 2-8 ml,respectively. 5-6% acidity distilled water vinegar

The treatment results in the lowering of the pH of the product that arepackaged in gas permeable bag (breathable), due to the interaction ofthe solubilized lower pH processing aid (co-solvent) formulations withthe product. This interaction over time leads to the impregnation of theprocessing aid (co-solvent)s within the cellular structure of theproduct which results in the inactivation of the enzyme, since theenzymatic activity is known to be dependent on the pH of the product.The lower pH is also known to act as a barrier/control point for thegrowth of various pathogenic and spoilage micro-organisms.

Example 2 Various Embodiments of Process Parameters for Shelf-LifeExtension of Fresh-Cut Vegetables

Various embodiments of the processes of the present disclosure areprovided below.

In one embodiment of the process of the present disclosure, the processcan involve the following combination of steps: (i) Peeling; (ii)Cutting (length—0.8 cm; width—0.6 cm; breath—0.6 cm); (iii) Blanching(65-90° C. for 5-15 minutes); (iv) Air drying (50-100° C. for 10-25minutes); (v) Supercritical CO₂+ethanol (150-350 Bar; 50-90° C.; CO₂flow rate 2-100 L/minute to provide a residence time of 10 seconds to 1minute; Ethanol flow rate 2-8 mol of the CO₂ flow rate %) @ 10-45minutes {continuous flow}; (vi) Depressurization of the vessel; (vii)Supercritical CO₂ (150-350 Bar; 50-90° C.; CO₂ flow rate 2-100 L/minuteto provide a residence time of 10 seconds to 1 minute) @ 10-45 minutes,Final moisture removal—40-45% {continuous flow}; (viii) Depressurizationof the vessel; and (ix) Vacuum packaging.

In another embodiment of the process of the present disclosure, theprocess can involve the following combination of steps: (i) Peeling;(ii) Cutting (length—0.8 cm; width—0.6 cm; breath—0.6 cm); (iii)Blanching (65-90° C. for 5-15 minutes); (iv) Supercritical CO₂+ethanol(150-350 Bar; 50-90° C.; CO₂ flow rate 2-100 L/minute to provide aresidence time of 10 seconds to 1 minute; Ethanol flow rate 2-8 mol ofthe CO₂ flow rate %) @ 10-45 minutes {continuous flow}; (v)Depressurization of the vessel; (vi) Supercritical CO₂ (150-350 Bar;50-90° C.; CO₂ flow rate 2-100 L/minute to provide a residence time of10 seconds to 1 minute) @ 10-45 minutes, Final moisture removal—40-45%{continuous flow}; (vii) Depressurization of the vessel; and (viii)Vacuum packaging.

In another embodiment of the process of the present disclosure, theprocess can involve the following combination of steps: (i) Peeling;(ii) Cutting (length—0.8 cm; width—0.6 cm; breath—0.6 cm); (iii)Blanching (85° C.@10 minutes); (iv) Air drying (85° C.@ 25-30 minutes),Allowing 18-19% moisture removal; (v) Supercritical CO₂+ethanol (300bar; 80° C.; CO₂ flow rate—4 l/min; Ethanol flow rate—4 mol %) @ 15-20minutes {continuous flow}; (vi) Depressurization of the vessel; (vii)Supercritical CO₂ (300 bar; 80° C.; CO₂ flow rate—4 l/min) @ 15-20minutes, Final moisture removal—40-45% {continuous flow}; (viii)Depressurization of the vessel; and (ix) Vacuum packaging.

In another embodiment of the process of the present disclosure, theprocess can involve the following combination of steps: (i) Peeling;(ii) Cutting (length—0.8 cm; width—0.6 cm; breath—0.6 cm); (iii)Blanching (85° C.@10 minutes); (iv) Supercritical CO₂+ethanol (300 bar;80° C.; CO₂ flow rate—4 l/min; Ethanol flow rate—4 mol %) @ 15-20minutes {continuous flow}; (v) Depressurization of the vessel; (vi)Supercritical CO₂ (300 bar; 80° C.; CO₂ flow rate—4 l/min) @ 15-20minutes, Final moisture removal—40-45% {continuous flow}; (vii)Depressurization of the vessel; and (viii) Vacuum packaging.

In another embodiment of the process of the present disclosure, theprocess can involve the following combination of steps: (i) Peeling;(ii) Cutting (length—0.8 cm; width—0.6 cm; breath—0.6 cm); (iii)Blanching (85° C.@10 minutes); (iv) Air Drying; (85° C.@ 25-30 minutes)(v) Packaging in breathable bags; (vi) Supercritical CO₂+apple juiceconcentrate or 5% distilled water vinegar (300 bar; 100° C. @ 15-20minutes {non-continuous flow}; (vii) Depressurization of the vessel.

In another embodiment of the process of the present disclosure, theprocess can involve the following combination of steps: (i) Peeling;(ii) Cutting (length—0.8 cm; width—0.6 cm; breath—0.6 cm); (iii)Blanching (85° C.@10 minutes); (iv) Packaging in breathable bags; (v)Supercritical CO₂+apple juice concentrate or 5% distilled water vinegar(300 bar; 100° C. @ 15-20 minutes {non-continuous flow}; (v)Depressurization of the vessel.

In another embodiment of the process of the present disclosure, theprocess can involve the following combination of steps: (i) Peeling;(ii) Cutting (length—0.8 cm; width—0.6 cm; breath—0.6 cm); (iii)Blanching (85° C.@10 minutes); (iv) Air drying (85° C.@ 25-30 minutes),Allowing 18-19% moisture removal; (v) Supercritical CO₂+ethanol (300bar; 80° C.; CO₂ flow rate—4 l/min; Ethanol flow rate—4 mol %) @ 15-20minutes {continuous flow}; (vi) Depressurization of the vessel; (vii)Supercritical CO₂ (300 bar; 80° C.; CO₂ flow rate—4 l/min) @ 15-20minutes, Final moisture removal—40-45% {continuous flow}; (viii)Depressurization of the vessel; (ix) Packaging in breathable bags; (x)Supercritical CO₂+apple juice concentrate or 5% distilled water vinegar(300 bar; 100° C. @ 15-20 minutes {non-continuous flow}; (xi)Depressurization of the vessel.

In another embodiment of the process of the present disclosure, theprocess can involve the following combination of steps: (i) Peeling;(ii) Cutting (length—0.8 cm; width—0.6 cm; breath—0.6 cm); (iii)Blanching (85° C.@10 minutes); (iv) Supercritical CO₂+ethanol (300 bar;80° C.; CO₂ flow rate—4 l/min; Ethanol flow rate—4 mol %) @ 15-20minutes {continuous flow}; (v) Depressurization of the vessel; (vi)Supercritical CO₂ (300 bar; 80° C.; CO₂ flow rate—4 l/min) @ 15-20minutes, Final moisture removal—40-45% {continuous flow}; (vii)Depressurization of the vessel; (viii) Packaging in breathable bags;(ix) Supercritical CO₂+apple juice concentrate or 5% distilled watervinegar (300 bar; 100° C. @ 15-20 minutes {non-continuous flow}; (x)Depressurization of the vessel.

Process parameters of various embodiments of the process of the presentdisclosure are identified in table form in Table 2 and Table 3, shownbelow.

TABLE 2 Various Processing Parameters of Embodiments of the Process ofthe Present Disclosure Super-Critical CO₂ SCCO₂ Blanching Air Dryingwith Ethanol without Ethanol Packaging Super-Critical CO₂ 85° C. @ 1085° C. @ 25 250-300 bar 250-300 bar Done in breathable 250-300 barminutes minutes 60-80° C. 60-80° C. bags with processing 80-90° C. CO₂flow rate: 4 L/min CO₂ flow rate: aid (co-solvent) Time of Run - Ethanolflow rate: 4 mol % 4 L/min (2-4% of mass of 15 minutes of CO₂ flow rateTime of Run- product packaged) Time of Run- 15 minutes 15 minutesStorage period - 45 days Storage condition - room temperature (20° C.)

TABLE 3 Various Parameters of Embodiments of the Method of the PresentDisclosure Method of Preparation Time Temperature Frying 2-3 minutes350° F. Baking 4-5 minutes 350° F.

Example 3 Shelf-Life Extension of Potato Products Material and MethodsPreparation of Potato:

Potato were peeled and cut in the standard dimensions of French fries:length-5.90 cms; breath—0.8 cms; width—0.8 cms. The initial moisturecontent of the potato was calculated by drying the samples at 105° C.for 48 hours. The moisture content of the potato was calculated to be78% on the basis of the mass loss, before and after drying.

Supercritical CO₂ Drying:

During the process, CO₂ from a cylinder (at 750 psi) was passed to apump, which compresses the CO₂. The compressed CO₂ was preheated to thedesired temperature with a heating element. Once the desired temperatureand pressure was attainted for the CO₂ in the vessel, the exit valveswere opened to attain a constant flow rate of the CO₂ through theproduct placed in the vessel. An external high pressure pump wasattached to the system to inject the ethanol at a desired flow rate. Atthe end of the experiment the ethanol flow was stopped and the productwas further treated with only supercritical CO₂ to remove the remainingprocessing aid (co-solvent) from the samples in the vessel. At the endof the process the vessel was depressurized. The samples were removedand weighed. By calculating the loss of mass: initial mass of thesample−final mass of the sample after processing with supercritical CO₂,the loss of moisture from the product was calculated and the wateractivity of the product was instrumentally measured. The measurementsfor the final product dimensions were made using a Vernier caliper.

Media Preparation:

PDA: The 15 grams of potato dextrose agar was mixed in 1 liter ofdeionized water. It was mixed well, then autoclaved at 121° C. cycle.The media was then poured into the petri plates and stored in therefrigerator at 4-7° C. until used.

PCA: The 15 grams of agar media was mixed in 1 liter of deionized water.It was mixed well, then autoclaved at 121° C. cycle. The media was thenpoured into the petri plates and stored in the refrigerator at 4-7° C.until used.

Peptone Water: 15 grams of peptone was mixed in 1 liter of deionizedwater. It was mixed well, then it was poured into the 10 ml test tubesand the 25 ml screw caped test tubes. Then these were autoclaved at 121°C. cycle. In each 10 ml test tube 9 ml of peptone water was poured forthe serial dilution. And in the 25 ml ones, 20 ml was poured which wereused for the stomaching the samples before plating.

Microbial Activity Determination:

The stored samples were opened up and placed into the stomacher bag andthe 20 ml of peptone water was added to it. Then these samples wereplaced in the stomacher for 3 min at 250 rpm. Then 1 ml of the peptonesolution was pipetted out from the bag and was added to the 9 ml testtube of peptone water. The serial dilution were done up till 10⁻⁶maximum. Then 1 ml of the solution was pipetted out of the serialdiluted tube 10⁻⁶ which were emptied into three petri plates of the PDAand PCA respectively. It was spread uniformly around the whole plate andwere stored at the 30° C. for 48 hours to calculate the total platecount using the below formula:

Initial dilution*subsequent dilution*amount plated=dilution factor

Reciprocal of dilution factor*colonies formed=cfu/gm

Polyphenol Oxidase (PPO) Activity Measurement:

Enzymatic activity was assayed by the method proposed by (Gui, et al.,2005) with modifications. The substrate solution consists of thephosphate buffer solution (PBS-0.05M, pH-6.0) containing 0.05Mcathechol. 10 grams of potato was taken and added to 25 ml of thesubstrate solution and were incubated at 30° C. for 50 minutes. PPOactivity was determined by measuring the absorbance of the mixture at420 nm, using spectrophotometer at the ambient temperature (25° C.). ThePPO activity was determined as the change in the absorbance at 420nm/min and per milliliter of potato sample. The relative activities ofthe PPO were obtained with the following formula:

${{Residual}\mspace{14mu} {Activity}} = \frac{{specific}\mspace{14mu} {activity}\mspace{14mu} {of}\mspace{14mu} {PPO}\mspace{14mu} {treated}\mspace{14mu} {with}\mspace{14mu} {SCCO}_{2}*100\%}{{Specific}\mspace{14mu} {activity}\mspace{14mu} {of}\mspace{14mu} {PPO}\mspace{14mu} {before}\mspace{14mu} {SCCO}_{2}}$

Example 4 Shelf-Life Extension of Potato Products Material and MethodsPreparation of Potato:

Potato were peeled and cut in the standard dimensions of French fries:length, 5.90 cm; breadth, 0.8 cm; and width, 0.8 cm.

Supercritical Carbon Dioxide Process:

The potato samples were packaged in gas permeable bag (breathable) andthe processing aids (co-solvents) (4% of the mass of potato) were placedin the bag along with the potatoes. The bags were sealed and placedinside a high-pressure treatment vessel. During the process, the CO₂from the cylinder (at 750 psi) pressurized to the desired pressure by apump preheated to the desired temperature with a heating element andinjected into the treatment vessel. The pressurized vessel was leftstatic for a predetermined time. Then the vessel was depressurizedswiftly to bring the carbon dioxide to gas phase and emptied slowly.

Measurement of the pH:

The potato samples were taken out from the processed bag and 5 gm ofrandom sample was taken. The sample was kept on the tissue paper toremove any residue of the condensation from the packaging. Then thesamples were cut into small pieces and mashed to make a paste with theaddition of DI water, if required. The pH probe was dipped into thesolutions to measure the pH.

Measurement of the Reflectance:

A color dye such as Disperse Blue 79 was placed in 0.1% of mass ofpotato along with the processing aid (co-solvent) in the bag. Once theprocess was complete, random 5 gram sample was taken from the processedbag and various cross-sections of the samples were made. The reflectanceof the various cross-sections of the samples was measured using a SP600⁺spectrophotometer at a wavelength of 700 nm.

REFERENCES

Citation of a reference herein shall not be construed as an admissionthat such reference is prior art to the present invention. Allreferences cited herein are hereby incorporated by reference in theirentirety. Below is a listing of various references relating to thepresent disclosure:

-   1. Bernadette Revel-McInnis Davis, A. G. (2016). U.S. Pat. No.    9,271,511 B2.-   2. Borisenok, J. G. (1991). U.S. Pat. No. 4,988,523A.-   3. Brown, Z., Fryer, P., Norton, I., & Bridson, R. (2010). Drying of    agar gels using supercritical carbon dioxide. the journal of    supercritical fluids, 89-95.-   4. Eisenhut, T. W. (2006). U.S. Pat. No. 7,108,832B2.-   5. Frederick G, K., & Kirkwood, J. G. (1930). The Dielectric    Constant of carbon dioxide as a function of temperature and density.    Physics review, 754-761.-   6. Fryer, Norton, P., bakalis, I., & bridson, S. &. (2007). Drying    of foods using supercritical carbon diooxide—Investigation with    carrot. Innovative Food Science & Emerging technologies., 280-289.-   7. Gui, F., Wu, J., Chen, F., Liao, X., Hu, X., Zhang, Z., &    Wang., Z. (2005). Inactivation of poyphenol oxidase in cloudy apple    juice exposed to supercritical carbon dioxide. Journal of Food    Chemistry, 1678-1685.-   8. King, M., Mubarak, A., & Kim, J. &. (2005). the mutual solubility    of water with supercritical and liquid carbon dioxide. Journal of    supercritical fluids, 296-302.-   9. Lee, C.-H. (1982). U.S. Pat. No. 4,336,273 A.-   10. Nijhuis, H., Torringa, H., Muresan, S., Yuksel, D., Leguijit,    C., & Kloek, W. (1998). Approaches to improving the quality of dried    fruit and vegetables. Trends in Food Science and Technology, 13-20.-   11. Oliveira, M., Abadias, M., Usal, J., Tones, R., Teixido, N., &    Vinas, I. (2015). Application of Modified Atmospheric pacakging as a    safety aproach to fresh cut fruits and vegetables. trends in food    science and technology, 13-26.-   12. Wimmer, Z., & Zarevucka, M. (2010). A Review on the effects of    Supercrititcal Carbon Dioxide on Enzyme Activity. International    Journal of Molecular Sciences, 233-253.

Illustrative embodiments of the processes, methods, and products of thepresent disclosure are described herein. It should be understood,however, that the description herein of the specific embodiments is notintended to limit the present disclosure to the particular formsdisclosed but, on the contrary, the intention is to cover allmodifications equivalents and alternatives falling within the spirit andscope of the invention by the appended claims. Thus, although thepresent invention has been described for the purpose of illustration, itis understood that such detail is solely for that purpose and variationscan be made by those skilled in the art without departing from thespirit and scope of the invention which is defined by the followingclaims.

What is claimed is:
 1. A process for improving shelf-life of fresh-cutvegetables, said process comprising the steps of: (i) blanchingunprocessed vegetable material comprising freshly cut vegetables,wherein said blanching increases cell structure permeability of thefreshly cut vegetables, thereby yielding a blanched vegetablepreparation that is enhanced for accelerated moisture removal via asupercritical fluids procedure; (ii) subjecting the blanched vegetablepreparation to a first supercritical fluids procedure to remove a firstpercentage of moisture therefrom, wherein the first supercritical fluidsprocedure is performed with a processing aid, thereby yielding anintermediate processed vegetable product infused with the processingaid; and (iii) performing a second supercritical fluids procedure to theintermediate processed vegetable product to remove a second percentageof moisture therefrom, wherein the second supercritical fluids procedureis performed without the processing aid, thereby yielding a finalprocessed vegetable product having improved shelf-life compared to thatof the unprocessed vegetable material.
 2. The process according to claim1, wherein the blanching is conducted at a temperature of between about65-90° C. for at least 5 minutes.
 3. The process according to claim 1,wherein the first supercritical fluids procedure is carried out at orabove supercritical pressures and temperatures and at a fluids flow rateat or above 1 liter/minute to provide a residence time of 10 seconds orabove with 2 percent or more of the processing aid of the total mass offreshly cut vegetables for 1 minute or more.
 4. The process according toclaim 1, wherein the second supercritical fluids procedure is carriedout at or above supercritical pressures and temperatures and at a fluidsflow rate at or above 1 liter/minute to provide a residence time of 10seconds or above in absence of the processing aid for 1 minute or more.5. The process according to claim 1, wherein the first supercriticalfluids procedure and the second supercritical fluids procedure arecarried out under continuous flow.
 6. The process according to claim 1further comprising: air-drying the blanched vegetable preparation priorto subjecting it to the first supercritical fluids procedure, therebyfacilitating moisture removal from the blanched vegetable preparationduring the first supercritical fluids procedure.
 7. The processaccording to claim 6, wherein the air-drying step comprises drying atabout 50-250° C. for 1 minute or above.
 8. The process according toclaim 1 further comprising: reducing equilibrium pH of the finalprocessed vegetable product by contacting it with a reducing co-solvent.9. The process according to claim 8, wherein the equilibrium pH of thefinal processed vegetable product is reduced to below 4.6.
 10. Theprocess according to claim 8, wherein the reducing co-solvent isselected from the group consisting of ethanol, distilled water vinegar,vinegar, lemon juice, lemon juice concentrate, apple juice, apple juiceconcentrate, cumin seed, ginger, garlic, lactic acid, gluconic acid,malic acid, peroxyacetic acid, tartaric acid, acetic acid and itsderivatives, sodium bisulfate, gluconodeltalactone (GDL), citric acid,buffers of such acids, and oleoresins.
 11. The processes according toclaim 1, wherein the vegetables are selected from the group consistingof potato, sweet potato, yam, artichoke, radish, carrot, turnip, beetroots, other root vegetables, and other non-root/tuber vegetables. 12.The process according to claim 1, wherein the percentage of moistureremoved from the unprocessed vegetable material is between about 1-80percent.
 13. The process according to claim 1, wherein the processingaid is a co-solvent selected from the group consisting of ethanol,distilled water vinegar, vinegar, lemon juice, lemon juice concentrate,apple juice, apple juice concentrate, cumin seed, ginger, garlic, lacticacid, gluconic acid, malic acid, peroxyacetic acid, tartaric acid,acetic acid and its derivatives, sodium bisulfate, gluconodeltalactone(GDL), citric acid, buffers of such acids, and oleoresins.
 14. Theprocess according to claim 1, wherein the first supercritical fluidsprocedure and the second supercritical fluids procedure are carried outusing a supercritical fluid selected from the group consisting of carbondioxide, nitrous oxide, ethanol, propane, ethylene, and acetone.
 15. Theprocess according to claim 1, wherein the first percentage of moistureremoved is at least 1% percent.
 16. The process according to claim 1,wherein the second percentage of moisture removed is at least 0.5%percent.
 17. The process according to claim 1, wherein if the freshlycut vegetables include a peel, the blanching step is performed with thefreshly cut vegetables with and/or without the peel.
 18. The processaccording to claim 1, wherein the improved shelf-life of the finalprocessed vegetable product comprises a water activity (A_(w)) below0.93.
 19. A food product comprising the final vegetables productprepared by the process according to claim
 1. 20. A process forimproving shelf-life of fresh-cut vegetables, said process comprisingthe steps of: (i) blanching unprocessed vegetable material comprisingfreshly cut vegetables, wherein said blanching increases cell structurepermeability of the freshly cut vegetables, thereby yielding a blanchedvegetable preparation that is enhanced for infusion of a processing aidwithin the cell structure of the freshly cut vegetables via asupercritical fluids procedure; (ii) packaging the blanched vegetablepreparation in a sealed gas permeable/breathable container with adefined volume of 0.001% or above of one or more processing aid; (iii)subjecting the blanched vegetable preparation within the sealed gaspermeable/breathable container to a supercritical fluids procedure at orabove supercritical temperatures and pressures, thereby yielding apressurized blanched vegetable preparation contained in the gaspermeable/breathable container; and (iv) depressurizing the pressurizedblanched vegetable preparation quickly to convert the supercriticalfluids to a gas phase followed by a slow depressurization stage, therebyyielding a final vegetable product having an improved shelf-lifecompared to the unprocessed vegetable material.
 21. The processaccording to claim 20, wherein the blanching is conducted at atemperature of between about 65-90° C. for about 5 minutes or above. 22.The process according to claim 20 further comprising: air-drying theblanched vegetable preparation prior to subjecting it to thesupercritical fluids procedure, thereby facilitating moisture removalfrom the blanched vegetable preparation during the supercritical fluidsprocedure.
 23. The process according to claim 20, wherein thesupercritical fluids procedure is carried out at no-flow conditions (0liters/minute).
 24. The processes according to claim 20, wherein thevegetables are selected from the group consisting of potato, sweetpotato, yam, artichoke, radish, carrot, turnip, beet roots, other rootvegetables, and other non-root/tuber vegetables.
 25. The processaccording to claim 20 further comprising: reducing equilibrium pH of thefinal processed vegetable product by contacting it with a reducingco-solvent.
 26. The process according to claim 20, wherein theprocessing aid is a co-solvent selected from the group consisting ofethanol, distilled water vinegar, vinegar, lemon juice, lemon juiceconcentrate, apple juice, apple juice concentrate, cumin seed, ginger,garlic, lactic acid, gluconic acid, malic acid, peroxyacetic acid,tartaric acid, acetic acid and its derivatives, sodium bisulfate,gluconodeltalactone (GDL), citric acid, buffers of such acids, andoleoresins.
 27. The process according to claim 20, wherein thesupercritical fluids procedure is carried out using a supercriticalfluid selected from the group consisting of carbon dioxide, nitrousoxide, ethanol, propane, ethylene, and acetone.
 28. A food productcomprising the final vegetable product prepared by a process accordingto claim
 20. 29. A process for improving shelf-life of fresh-cutvegetables, said process comprising the steps of: (i) performing theprocess according to claim 1 to yield a first final processed vegetableproduct; (ii) packaging the first final processed vegetable product in asealed breathable film bag with a defined volume of one or moreco-solvent; (iii) subjecting the first final processed vegetable productwithin the sealed breathable film bag to a third supercritical fluidsprocedure along with temperature variations, thereby yielding apressurized first final processed vegetable product contained in thesealed breathable film bag; and (iv) depressurizing the pressurizedfirst final processed vegetable product quickly to convert thesupercritical fluids to a gas phase followed by a slow depressurizationstage, thereby yielding a completed vegetable product having an improvedshelf-life compared to the unprocessed vegetable material.
 30. A foodproduct comprising the completed vegetable product prepared by theprocess according to claim 29.